判断字符串是否由数字和字母组成

#import <Foundation/Foundation.h>
/**
*  判断字符串是否是由字母和数字组成
*
*  @param str 要判断的字符串
*
*  @return YES(只有字符串和数字) NO(只有字符串或者只有字母)
*/
BOOL adjustString(NSString * str)
{
// 数字的个数
NSInteger numberCount = 0;
// 字母的个数
NSInteger alphabetCount = 0;
str = [str lowercaseString];
const char *cStr = [str UTF8String];
NSInteger cStrLength = strlen(cStr);
for (int i = 0; i < cStrLength; i ++)
{
if (cStr[i] >='0' && cStr[i]<= '9')
{
numberCount ++ ;
}
else
{
if (cStr[i]>='a' && cStr[i]<= 'z')
{
alphabetCount ++;
}
else
{
return NO;
}
}
}
return (numberCount && alphabetCount);
}

int main(int argc, const char * argv[]) {
@autoreleasepool {

NSLog(@"%@",@(adjustString(@"123abs")));
NSLog(@"%@",@(adjustString(@"123abs123")));
NSLog(@"%@",@(adjustString(@"123absv ")));
}
return 0;
}